ASUS GL502VS - HDMI Display OK, LCD No Go

[limxrich]

Hello. Need some other viewpoints.

- LCD is tested OK
- LCD Flex - spare purchased and tested - no go
- HDMI Displays ok
- HPD voltage on HDMI goes high when plugged in (5v)
- HPD voltage on EDP goes high when plugged in (2.4v)
- L+3VS_LCD - 3V ok
- AC_BAT_SYS_LCD - 19V ok
- LCD_BLEN_CON - 1.4V

Would appreciate everyone's input. Thanks!

[Sephir0th]

Re: ASUS GL502VS - HDMI Display OK, LCD No Go

Backlight Enable low, so you have "just" missing backlight?

[reformatt]

Re: ASUS GL502VS - HDMI Display OK, LCD No Go

LCD_BLEN_CON does seem an odd voltage, given it's coming from an AND gate. Would've expected 3V there. Also check duty cycle of backlight PWM varies when brightness adjusted up/down with a scope. Check FRAME_LOCK#, LCD_VDD_EN if missing.

[limxrich]

Re: ASUS GL502VS - HDMI Display OK, LCD No Go

Injected 3V to backlight LCD_BLEN_CON_X1 and it just lights up, no image whatsoever.

[limxrich]

Re: ASUS GL502VS - HDMI Display OK, LCD No Go

LCD_BLEN_CON does seem an odd voltage, given it's coming from an AND gate. Would've expected 3V there. Also check duty cycle of backlight PWM varies when brightness adjusted up/down with a scope. Check FRAME_LOCK#, LCD_VDD_EN if missing.

Yup, I thought it was odd too, injecting 3v there made the screen light up, but no image. Frame lock at 2.4V, LCD_EN at 2.2V